me thinks you will have to get down and dirty on this one. you are going to have to look at exactly what the phone is sending - i am not sure if you can get everything simply by turning up the verbosity on the console but it is worth a try. if not then turn on the packet capture in the yealink phone and use tcpdump to capture the traffic from the phone and to/from the pbx. i like wireshark to view the captured files.
what you do know is if the transfer is properly completed (## plus extension) it does work. what you also know is that using a button (set as blf or transfer) does not work.
you should be able to see what happens on a successful transfer (no ghost call) and to see what is different when using the blf key.
Thanks for the reply! Yes definitely a PITA. PLease let me know how you make out. Iām going to be trying a few other things in the meantime (Different Firmware, Changing timeouts, etc.) Thereās like zero info about this on Google.
Thanks Rudy! This is a tough one to troubleshoot. Any idea if the firmware on the phones changed when you went with the cloud provider? Just asking because it seems like a Yealink issue.
No. Firmware stayed the same. On the T23G we are running Firmware Version 44.80.0.95
Hardware Version 44.0.0.16.0.0.0 For the T29G Firmware Version 46.80.0.70
Hardware Version 46.0.0.128.0.0.0.
The server is VMWare, not sure about the version of ESX nor hardware it is running on. We do have a VPN connection between our network and theirs. Maybe the sonicwall is filtering something, although in the logs (set on debug currently) there is nothing being recorded.
Thanks again for the info. Now Iām wondering if it might be a network related because it doesnāt seem like many people are experiencing the issue. Do you know if youāre using chan_sip or pjsip for your extensions on the cloud? Sorry to be a pest but this is driving me crazy!
The OP has posted a workaround. This would make sense why Daniel didnāt have the issue after he moved to the cloud. The VOIP provider is probably blocking or rewriting the 503 packets.